In recent years, mobile terminals such as portable telephones and PHS (Personal Handy phone System) terminals are widely spread, so that it is possible to make a call or to obtain information regardless of location or time. In particular, an amount of information that can be obtained is recently increased and a wireless communication method of high speed and high quality is adopted so as to download a large amount of data. As the information that can be handled and the amount and number of applications are increased, a help function for searching contents, functions and operating methods thereof is required. However, the mobile terminal has the limited number of input keys and the limited display area so as to keep the portability thereof and the operability of the help function itself is poor, so that it is not possible to provide sufficient search efficiency.
In order to improve the search efficiency by keywords, a technique has been disclosed in which after a key input operation is performed, a function explanation database is searched based on history of the key input operation and proper help information can be searched on the basis of keywords, which have been already input, without re-input of keywords (for example, Patent Document 1). In addition, a technique has been known in which when any information is searched using a help function, not only an input of a key or request sentence for search but also operation history is also considered to search help information that a user desires (for example, Patent Document 2).
In the meantime, the information of the contents, functions and operation methods can be typically referred to via a plurality of hierarchies (via selection items) from menu items. However, a user has to always pass through a plurality of hierarchies so as to refer to the information, so that the user is forced to have a troublesome operation and specialized knowledge. Accordingly, a technique has been also disclosed in which an operation screen, in which a plurality of menu items is arranged in order of using frequency while ignoring a hierarchy relation of items, is displayed so that the information, which has been once used, can be easily referred to from next time (for example, Patent Document 3). According to the technique, it is possible to easily select a desired function setting without repeating a complicated menu selecting operation.